Improving knowledge of cyclist crashes based on hospital data including crash descriptions from open text fields

Trends in bicycle related injuries in children 0-9 years of age in an urban Danish population 1980-2023

INTRODUCTION

The aim of the study is to describe the development of bicycle related injuries over the last four decades among young children and to describe their role as a passenger or cyclist.

METHODS

Retrospective study of 7368 children aged 0-9 years that sustained a bicycle related injury in the period 1980-2023. Incidence rates (IR) where analyzed in three age groups; 0-2 years, 3-5 years and 6-9 years. Data was analyzed in regards to age, gender, severity of injury, usage of bicycle helmet and whether the child was a cyclist or a passenger on a bike.

RESULTS

Bicycle related injury accounted for 74.5 % of all traffic related injuries for children 0-9 years treated at Odense University Hospital, Denmark 1980-2023. There was a decrease in IRs for all age groups and both genders in the study period with an overall IR decrease by 69.0 %. The IR for major and minor injury decreased for all age groups and both genders with an overall decrease of 75.6 % and 84.8 %, respectively. In the study period, 85.0 % of children were injured as cyclists and 15.0 % as passengers.

CONCLUSIONS

The study showed a significant decrease in overall IR when stratifying by age, gender, injury severity and the role of the child as cyclist or passenger. The study provides useful information for future studies and campaigns regarding children's bicycle safety.

Comparative modeling of risk factors for near-crashes from crowdsourced bicycle airbag helmet data and crashes from conventional police data

INTRODUCTION

Conventional cycling crash data is valuable for shaping safe cycling environments but has limitations due to the rarity and under-reporting of cycling crashes. However, recent technological developments can provide information from near-crashes. the subheads should be italic, not bf. Also in the Abstract, there shouldn't be hard return between subheads, the whole section should all run together, so run up any text between subheads.

METHOD

With Metropolitan Copenhagen as a case, this study uses a very large crowdsourced near-crash dataset from Hövding bicycle airbag helmet users and conventional police crash data to model and identify differences in the infrastructure factors influencing rates of crashes and near-crashes in these datasets.

RESULTS

In contrast to existing literature, our results show considerable differences in the factors influencing the frequency of crashes and near-crashes. The risk of crashes increases predominantly at intersections and roundabouts, whereas near-crashes are also associated with infrastructure types shared with pedestrians.

CONCLUSION

When used complementarily, crowdsourced near-crash data can enrich the data foundation and help increase the awareness of near-crash-prone infrastructure types necessary for shaping more comprehensive cycling safety policies.

PRACTICAL APPLICATIONS

The findings of the study advocate for a broader perspective on cyclist safety, incorporating currently undisclosed near-crash-prone infrastructure types, such as paths shared by cyclists and pedestrians.

Comparison of single bicycle crashes and collisions among severely injured cyclists-A 16-year analysis based on the Helsinki Trauma Registry (HTR)

OBJECTIVE

The Finnish national Traffic Safety Strategy 2022-2026 seeks to halve the number of road fatalities and serious injuries from 2020 to 2030. The strategy states that better information on bicycle crashes is needed for safety promotion. The aim of this study was to describe the demographics, injury characteristics, alcohol involvement, and helmet use of severely injured cyclists and to compare single bicycle crashes (falling alone or hitting a fixed object) to collisions.

MATERIAL AND METHODS

We identified all bicycle crashes between 2006 and 2021 from the Helsinki Trauma Registry (HTR). Variables analysed were basic patient demographics, Abbreviated Injury Scale (AIS) codes, AIS 3+ injuries, injured body regions, patient Injury Severity Score (ISS) and New Injury Severity Score (NISS), 30-day in-hospital mortality, ICU length of stay, injury mechanism, alcohol use by the injured cyclists, and helmet use.

RESULTS

Of the 325 severe (NISS >15) cycling injury patients in the HTR, 53.5 % were injured in single crashes and 46.5 % in collisions with a moving object. Most (71.4 %) patients were men and mean age of all patients was 54.1 years (SD 16.7). Alcohol was detected in 23.1 % of cases and more often in single crashes (32.8 %) than in collisions (11.9 %). Less than a third (29.2 %) of all cyclists wore a helmet; those who wore a helmet had fewer serious (AIS 3+) head injuries than those who did not. Cyclists injured in collisions had higher ISS and NISS scores than those injured in single crashes. Serious (AIS 3+) injuries in extremities or in pelvic girdle were more common in collisions than in single crashes.

CONCLUSIONS

Among severely injured cyclists, single bicycle crashes were more common; alcohol was more often detected in single bicycle crashes than in collisions. Overall injury severity was higher in collisions than in single crashes. Helmet users had less AIS 3+ head injuries than non-users. Attention should be focused on preventing alcohol-related cycling injuries, promoting use of bicycle helmets, and more precise and comprehensive documentation of bicycle crashes in health care units.

The effect of rear bicycle light configurations on drivers' perception of cyclists' presence and proximity

The optimal cycle light configuration for maximizing cyclists' conspicuity to drivers is not clear. Advances in sensor technology has led to the development of 'reactive' cycle lights that detect changes in the environment and consequently increase their flashing speed and brightness in risky situations - for example, when a rearward car is approaching - but no research has examined the effect of such lights on driver perception. The aim of the present study is to compare different cycle light configurations, including 'reactive' light technology, on drivers' ability to detect cyclists and estimate their proximity. We recruited 32 drivers to participate in two experiments, in which they viewed life-size real-world stimuli filmed from a driver's perspective in daytime and at dusk. The footage showed a cyclist on a bicycle with a rear light mounted on the seat post, in various configurations: static light, steady flashing, reactive flashing and no light. In Experiment 1, the drivers were required to detect the presence or absence of a cyclist on the road ahead as quickly as possible. In Experiment 2, they were required to estimate the distance of the cyclist from their vehicle, and to rate their confidence in their estimates. Experiment 1 revealed that drivers were quicker to detect the cyclist's presence in all rear cycle light conditions relative to the no light condition, but there were no differences in speed or accuracy across rear light conditions. Experiment 2 showed that drivers were more accurate in estimating the cyclist's proximity in the steady flashing and reactive flashing conditions, compared to static and no light conditions. Drivers were also more confident in their judgements in all rear light conditions compared to the no light condition. In conclusion, flashing rear cycle lights, regardless of reactive technology, enhanced drivers' perception of a cyclist ahead, notably in terms of their judgements of distance to that cyclist. Further investigation is needed to fully understand the impact of cycle light technology on driver perception, as well as the use of drivers' distance-to-cyclist estimates as an index of cyclists' cognitive conspicuity.

Single-bicycle crashes in Finland - Characteristics and safety recommendations

PROBLEM

Increasing the role of cycling is necessary to reduce physical inactivity. While promoting cycling, attention should also be given to traffic safety. Hence, a better understanding on the underlying factors and safety recommendations of cyclist crashes is needed. This study aims to increase knowledge on fatal single-bicycle crashes (SBCs), where other road users are not collided with.

METHOD

Data from in-depth investigated fatal cyclist crashes in Finland is analyzed from 2010 to 2019. The study presents descriptive analysis of the characteristics, underlying factors, and safety recommendations of SBCs (n = 82) and other cyclist crashes (n = 151). Logistic regression analysis and chi-squared tests were performed to identify significant characteristics for SBCs.

RESULTS

Fatal SBCs commonly involved people aged 60 or older, males, and cyclist not wearing a helmet. Cyclist's health issues influenced the crash in 62.2% of the SBCs. Compared to other cyclist crashes, health issues, alcohol, males, other crash locations than intersections, and weekends were highlighted in SBCs. Safety recommendations emphasized human factors, such as informing cyclist about underlying factors and the use of safety equipment.

DISCUSSION

In addition to human factors, the safety recommendations included suggestions regarding the bicycle, the traffic environment, and traffic regulations. This highlights the need to focus on different safety improvement actions to reduce SBCs. This study identified key characteristics of SBCs, which may help traffic safety authorities address this road safety issue and ultimately help to promote cyclist safety.

PRACTICAL APPLICATIONS

Cooperation between the actors including health care providers and the police is also proposed to address cyclists' health issues that contribute to SBCs.

Assessing bicycle crash risks controlling for detailed exposure: A Copenhagen case study

A better understanding of factors associated with bicycle crashes can inform future efforts to limit crash risks. Many previous studies have analysed crash risk based on crash databases. However, these can only provide conditional information on crash risks. A few recent studies have included aggregate flow measures in their crash risk analyses. This study incorporates detailed bicycle flow to investigate factors related to bicycle crashes. Specifically, the study assesses the relative crash risk given various conditions by applying Palm distributions to control for exposure. The study specifically investigates the relationship between weather and time conditions and the relative risk of bicycle crashes at a disaggregate level. The study uses bicycle crash data from police reports of bicycle crashes from 2017-2020 in the greater Copenhagen area (N = 4877). The relations between the bicycle crash risk and the air temperature and wind speeds are found to be highly non-linear. The relative risk of bicycle crashes is elevated at low and high temperatures (0 °C ¿ x, x ¿ 21 °C). The results also show how decreasing visibility relates to increasing bicycle crash risk. Meanwhile, cycling during the early morning peak (7-8) and afternoon peak hours (15-18) is related to an increased risk of bicycle crashes. While some of the effects are likely spurious, they highlight specific conditions associated with higher relative risk. Finally, the results illustrate the increased risk at weekend night times when cyclists are likely to bike under the influence of alcohol. In conclusion, the analysis confirms that visibility, slippery surfaces, and intoxication are all factors associated with a higher risk of bicycle crashes. Hence, it is relevant to consider how infrastructure planning and preventive measures can modify the bicycle environment to minimise these risks.